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PubMed2006

Optimization of a multinomial model for investigating hallucinations and delusions with source monitoring.

Studies of source monitoring have played an important role in cognitive investigations of the inner/outer confusions that characterize hallucinations and delusions in schizophrenia, and multinomial modelling is a statistical/cognitive modelling technique that provides a powerful method for analyzing source monitoring data. The purpose of the current work is to describe how multinomial models can be optimized to answer direct questions about hallucinations and delusions in schizophrenia research. To demonstrate this, we present a reanalysis of previously published source monitoring data, comparing a group of patients with schneiderian first rank symptoms to a group without schneiderian first rank symptoms. The main findings of this analysis were (1) impaired recognition of self-generated items and (2) evidence that impaired source discrimination of perceived items is accompanied by an internalization bias in the target symptom group. Statistical and cognitive interpretations of the findings are discussed.

Cognition Disorders↗
PubMed2006

Association of delusions and lack of cognitive flexibility with social anxiety in schizophrenia spectrum disorders.

Though often overlooked clinically, social anxiety appears to be unusually common in schizophrenia and may represent a barrier to quality of life and wellness. To explore the possible roots of social anxiety in schizophrenia, we concurrently assessed delusions using the Positive and Negative Syndrome Scale, flexibility of abstract thought using the Wisconsin Card Sorting Test, capacity for interpersonal relations using the Quality of Life Scale and social anxiety using the Liebowitz Social Anxiety Scale among 71 participants with schizophrenia or schizoaffective disorder. ANOVA revealed participants classified as having both significant delusions and impairments in flexibility of abstract thought (n=11) had significantly higher levels of social anxiety and fewer psychological resources for interpersonal relationships than participants with only one or neither of these difficulties. Groups did not differ on demographic variables, awareness of illness or negative symptoms. Clinical and theoretical implications are discussed.

Adult↗
PubMed2003

Delusions of alien control in the normal brain.

Delusions of alien control, or passivity experiences, are symptoms associated with schizophrenia in which patients misattribute self-generated actions to an external source. In this study hypnosis was used to induce a similar misattribution of self-generated movement in normal, healthy individuals. Positron Emission Tomography (PET) was employed to investigate the neural correlates of active movements correctly attributed to the self, compared with identical active movements misattributed to an external source. Active movements attributed to an external source resulted in significantly higher activations in the parietal cortex and cerebellum than identical active movements correctly attributed to the self. We suggest that, as a result of hypnotic suggestion, the functioning of this cerebellar-parietal network is altered so that self-produced actions are experienced as being external. These results have implications for the brain mechanisms underlying delusions of control, which may be associated with overactivation of the cerebellar-parietal network.

Adult↗
PubMed2000

Nurturing syndrome: a form of pathological bereavement with delusions in Alzheimer's disease.

We report the history and neuroimaging profile of two patients, CS and KC who developed an unusual bereavement reaction with delusions following the deaths of their husbands. Their neuropsychological profiles met criteria for dementia of Alzheimer type. The delusions about their husbands' existence were persistent despite a considerable passage of time after their deaths. SPECT investigation showed reduction of blood flow in the frontal area in both patients when compared with demented controls and in particular a significant reduction in perfusion was observed in the right frontal regions. We argue that this significant reduction of blood flow in the right frontal area, in the context of severe cognitive deterioration, might be responsible for their delusional reaction to bereavement which we interpret as result of reality monitoring and episodic memory failure.

Aged↗
PubMed2006

[Identification errors and delusions of false identification in Alzheimer's disease: a regional survey].

INTRODUCTION: Misidentification syndromes are the main symptoms in Alzheimer's disease. Underlain by complex cognitive, agnosic, and amnesic disturbances of degenerative etiology, they can be expressed by misidentification delusions, as in psychoses. To date, research has focused on identification disturbances of persons selected according to various definitions. OBJECTIVE: Our main objective was to evaluate the frequency of identification disturbances among patients suffering from Alzheimer's disease within the current conditions of diagnosis and treatment. The secondary objective aimed to establish a detailed analysis of symptoms and clinical correlations, and evaluate the effects of the troubles on the caregiver. METHODS: We conducted a regional survey using a questionnaire designed for the caregiver, proposed to the 60 geriatric doctors and neurologists in the Poitou-Charentes region of France, for all patients suffering from Alzheimer's disease (defined according to DSM IV criteria) seen between June 1st and August 31st of 2003. Statview software was used for statistical analysis. RESULTS: The survey was completed for 104 patients: 69.5 percent women and 30.5 percent men, with a mean age of 79 years. The majority of the patients were seen by a neurologist and presented an average cognitive deficiency (MMS ranging from 11 to 20). An identification disturbance, whether or not it was delusional, all domains included, was found in 81.6 percent of the patients and was related to a more severe cognitive deficiency and greater hardship on the part of the caregiver. DISCUSSION: We observed a high prevalence of identification disturbance, which can be explained by the systematic and exhaustive search for identification disturbance. The most frequent disturbance concerned the identification of places, whereas self-identification was less often affected; the authentic Capgras delusion was found less often. CONCLUSION: The study of identification disturbances in Alzheimer's disease can contribute to a better understanding of the cognitive, psychopathological, and physiopathological aspects of the disease as well as to a better knowledge and better care for the patient.

Aged↗
PubMed2001

SPECT neuroimaging in schizophrenia with religious delusions.

Functional neuroimaging techniques such as single-positron emission computed tomography (SPECT) and positron emission tomography (PET) offer considerable scope for investigating disturbances of brain activity in psychiatric disorders. However, the heterogeneous nature of disorders such as schizophrenia limits the value of studies that group patients under this global label. Some have addressed this problem by considering schizophrenia at a syndromal level, but so far, few have focussed at the level of individual symptoms. We describe the first neuroimaging study of the specific symptom of religious delusions in schizophrenia. 99mTc HMPAO high-resolution SPECT neuroimaging showed an association of religious delusions with left temporal overactivation and reduced occipital uptake, particularly on the left.

Adult↗
PubMed2001

Persecutory delusions: a review and theoretical integration.

Persecutory (paranoid) delusions are a frequently observed clinical phenomenon. In recent years, an increasing volume of research has attempted to explain these types of beliefs in terms of psychological mechanisms. Theories have emphasized early experience, perceptual abnormalities, motivational factors, and information-processing deficits. In this article we review relevant findings, including our own studies of the role of causal attributions and theory of mind deficits. We propose a new integrative model that builds on this work. The core of the model is an account of the way that causal attributions influence self-representations, which in turn influence future attributions: the attribution--self-representation cycle. We argue that biases in this cycle cause negative events to be attributed to external agents and hence contribute to the building of a paranoid world view. These abnormalities are amenable to investigation by functional neuroimaging, and recent studies have implicated specific areas of neuroactivation. However, these findings do not necessarily suggest that paranoid delusions are entirely biological in origin, and there is evidence that adverse early experience may play a role in determining the development of a cognitive vulnerability to paranoid thinking.

Cognition↗
PubMed1998

Individual cognitive-behavior therapy in the treatment of hallucinations and delusions: a review.

The limitations of biochemical treatments in reducing the severity of hallucinations and delusions has led to an increased interest in the investigation of psychological treatments for these symptoms. These investigations have spanned the last 4 decades and have covered a range of psychological approaches from psychoanalytically oriented psychotherapy to behavioral approaches. More recently, findings that some psychotherapies are not effective treatments for psychosis and that cognitive-behavior therapy can be an effective treatment for neurotic disorders have led to increasing interest in the investigation of the effectiveness of cognitive-behavior therapy for psychosis. This review describes and evaluates the research on the cognitive-behavioral treatment of hallucinations and delusions and describes the cognitive models from which the treatments have developed. The conclusion is that, on the whole, the literature provides fairly strong evidence for the efficacy of cognitive-behavioral approaches in the management of chronic psychotic disorders and associated symptoms, although there are a number of areas where further development is necessary.

Adaptation, Psychological↗
PubMed1996

Cognitive theory applied to the treatment of delusions of schizophrenia.

This article reviews theory regarding cognitive interventions in schizophrenia, focusing particularly on the treatment of delusions. The cognitive theory of psychopathology is first introduced and the specific goals of cognitive therapy are then presented. A range of philosophical and etiologic perspectives on the nature of delusions are explored, including the cognitive perspective. Specific stages and techniques of therapy are discussed with theoretical underpinnings and suggestions for incorporation in advanced practice psychiatric nursing.

Cognitive Behavioral Therapy↗
PubMed1998

Abnormal visual scan paths: a psychophysiological marker of delusions in schizophrenia.

The role of the visual scan path as a psychophysiological marker of visual attention has been highlighted previously (Phillips and David, 1994). We investigated information processing in schizophrenic patients with severe delusions and again when the delusions were subsiding using visual scan path measurements. We aimed to demonstrate a specific deficit in processing human faces in deluded subjects by relating this to abnormal viewing strategies. Scan paths were measured in six deluded and five non-deluded schizophrenics (matched for medication and negative symptoms), and nine age-matched normal controls. Deluded subjects had abnormal scan paths in a recognition task, fixating non-feature areas significantly more than controls, but were equally accurate. Re-testing after improvement in delusional conviction revealed fewer group differences. The results suggest state-dependent abnormal information processing in schizophrenics when deluded, with reliance on less-salient visual information for decision-making.

Adult↗
PubMed2004

Persecutory delusions and the determination of self-relevance: an fMRI investigation.

BACKGROUND: People with persecutory delusions regard ambiguous data in the social domain as self-relevant and selectively attend to threatening information. This study aimed to characterize these social cognitive biases in functional neuroanatomical terms. METHOD: Eight schizophrenic patients with active persecutory delusions and eight matched normal controls underwent functional magnetic resonance imaging while determining the self-relevance of ambiguous self-relevant or unambiguous other-relevant neutral and threatening statements. RESULTS: In determining self-relevance, the deluded subjects showed a marked absence of rostral-ventral anterior cingulate activation together with increased posterior cingulate gyrus activation in comparison to the normal subjects. The influence of threat on self-relevance determination did not yield statistically significant differences between deluded and normal subjects. CONCLUSIONS: Abnormalities of cingulate gyrus activation while determining self-relevance suggest impaired self-reflection in the persecutory deluded state. This may contribute to persecutory belief formation and maintenance.

Adult↗
PubMed2001

Caregiver report of hallucinations and paranoid delusions in elders aged 70 or older.

This study examined the demographic, medical, and psychiatric correlates of hallucinations and paranoid delusions reported by proxy informants for 822 elders aged 70 or older. This sample comprised people who were deemed unable to complete a direct interview in a large nationwide study of aging. Marital status, trouble with vision, and cognitive impairment were associated with report of both paranoid delusions and hallucinations. Depressive symptoms and stroke were associated with hallucinations only. These results suggest that inadequate external stimulation in the elderly leads to psychotic experiences.

Aged↗
PubMed2000

A narcoleptic patient exhibiting hallucinations and delusion.

A female narcoleptic patient with persistent auditory hallucinations and delusion is reported. These psychotic symptoms appeared before the diagnosis of narcolepsy and before the use of pemoline and clomipramine. On admission to the Department of Neuropsychiatry at the Kurume University school of Medicine, the patient's auditory hallucinations were almost the same as the previous hallucinations. The patient's delusional state improved smoothly after haloperidol administration. After that, the patient related well socially. The persistent auditory hallucinations were correlated with rapid eye movement sleep symptoms during her disease process so that we concluded that her persistent auditory hallucinations and delusion of observation were due to narcoleptic symptoms.

Delusions↗
PubMed1999

Delusions, superstitious conditioning and chaotic dopamine neurodynamics.

Excessive mesolimbic dopaminergic neurotransmission is closely related to the psychotic symptoms of schizophrenia. A mathematical model of dopamine neuron firing rates, developed by King and others, suggests a mechanism by which excessive dopaminergic transmission could produce psychotic symptoms, especially delusions. In this model, firing rates varied chaotically when the efficacy of dopaminergic transmission was enhanced. Such non-contingent changes in firing rates in mesolimbic reward pathways could produce delusions by distorting thinking in the same way that non-contingent reinforcement produces superstitious conditioning. Though difficult to test in humans, the hypothesis is testable as an explanation for a common animal model of psychosis--amphetamine stereotypy in rats. The hypothesis predicts that: (1) amphetamine will cause chaotic firing rates in mesolimbic dopamine neurons; (2) non-contingent brain stimulation reward will produce stereotypy; (3) non-contingent microdialysis of dopamine into reward areas will produce stereotypy; and (4) dopamine antagonists will block all three effects.

Amphetamine↗
PubMed1989

[Aspects of the dynamics of delusions].

Delusion ist the outcome of psychotic experience, but can also be seen as a structure of meaning with patterns of mental and anthropological significance of its own. In schizophrenic delusion, there is some 'effort after meaning' manifest, compensating for psychotic disintegration. In the light of generative linguistics, there seems creating of delusional ideas to be performed in separated steps, but contextually linked to integrate them into a holistic delusional view of reality. Subjective evidence of delusional thinking is analyzed on the basis of semantic logics.

Delusions↗
PubMed1989

Delusions and hallucinations as a reflection of the subcultural milieu among psychotic patients of the 1930s and 1980s.

Delusions and hallucinations reported in the social histories of 150 patients admitted to an East Texas state hospital during the 1930s and of 150 patients admitted during the 1980s were examined for content that would characterize and contrast the patient subcultural milieu of the two time periods. Patients admitted during the 1930s tended to reflect the material deprivation and personal powerlessness of the great depression in delusions of great wealth and positive "special powers." The hallucinatory visions and voices of the 1980s patients reflected a more threatening and negative subcultural milieu, with more visions of blood, snakes, and dead people or animals. Command hallucinations to hurt, to kill, or to do "perverse things" would also suggest that the subculture milieu of the 1980s had become more dangerous.

Adolescent↗
PubMed1996

To be or not to be at home? A neuropsychological approach to delusion for place.

A woman, LB, while in recovery from a viral encephalitis, exhibited a delusion for place, which led her to insist that she was at home, in spite of compelling evidence to the contrary. Later, she developed a Capgras syndrome, that is, another misidentification syndrome. The patient was given a detailed neuropsychological evaluation to shed light on the mechanisms underlying her delusional misbelief. Two main deficits were in evidence: (1) a severe visual-spatial impairment, giving the patient a distorted perception of her surroundings; and (2) frontal lobe dysfunction, which played a critical role in her impulsive responses and lack of self-awareness. The pathogenesis of delusion for place and persons if discussed in light of these observations.

Awareness↗
PubMed2006

Neuropsychological functioning and delusions in dementia: a pilot study.

The present pilot study investigated the pattern of neuropsychological functioning associated with the presence of delusions in mild-to-moderate dementia. Participants, all of whom met criteria for dementia, were divided into two groups, delusional (n = 9) and non-delusional (n = 9). Individuals with hallucinations were excluded. Participants completed a neuropsychological test battery. Global cognitive functioning (MMSE) and behavioral disturbance (BEHAVE-AD) were also assessed. Differences between the delusional and non-delusional group were most marked for immediate recall of stories, which was higher in the non-delusional group. Scores on semantic fluency, attention (mental control), and overall cognitive functioning (MMSE) were also lower in the delusional group. Conversely, simple attention span (Digit Span) was within normal limits in both groups. Floor effects were noted on measures of delayed recall and alternating attention. This study supports previous findings of greater neuropsychological impairment in delusional as compared to non-delusional individuals with dementia. However, some areas of cognitive functioning may be relatively preserved. Future research should examine semantic processing in persons with dementia with and without delusions.

Aged↗